EEG technology has advanced substantially with respect to digital processing capability during the past 20 years. However, the process of transducing the very small cerebral electrical signals at the scalp surface remains difficult, requiring very low and balanced contact impedances to achieve acceptable levels of line frequency (60 Hz) noise. Preparation of scalp sites using solvents, abrasives and syringe needles to match amplifier system input requirements is time consuming, costly and especially burdensome in neonatal and critical care patients. Based on Phase I success, a preparation-free EEG technology will be completed that would entirely eliminate scalp site preparation with solvents, abrasive compounds and needles, etc. Setup time for clinical and experimental protocols would be reduced to the time required to make physical contact. In addition to time savings, it will eliminate the need for shielded enclosures, simplify recordings in noisy environment such as intensive care units, and end patient irritation and the risk of infection from scalp puncture during abrasion. Two low-cost implementations of the technology will be developed: an EEG transduction module (ETM) to serve as a compact, in-line, modular retrofit to existing EEG/Evoked potential systems and an EEG System Module (ESM) that would serve as a complete amplifier system capable of connecting to notebook and desktop PC's equipped with a "Firewire" (IEEE 1394) serial bus port. The ETM will upgrade any EEG/EP system to "preparation-free" functionality and for most, substantially improve overall signal-to-noise performance. The ESM software package will feature object-oriented programmability, conferring unprecedented user control and flexibility. Both devices will enable the uncomplicated use of electrode caps. Production versions of both devices will be field tested at established clinical and research sites, providing realistic opportunities to identify and correct weaknesses or "bugs."